package vm_test

import (
	"jinx/pkg/lang/vm"
	"jinx/pkg/lang/vm/code"
	"jinx/pkg/lang/vm/text"
	"strings"
	"testing"

	"github.com/stretchr/testify/require"
)

func TestSimpleSub(t *testing.T) {
	src := `
	push_int 1
	push_int 2
	sub
	`

	test(t, src, "1")
}

func TestGetLocal(t *testing.T) {
	src := `
	push_int 404
	push_int 1
	push_int 2
	add
	get_local 1
	`

	test(t, src, "3")
}

func TestFibonacci(t *testing.T) {
	src := `
	# Array stored in local 0
	push_array 

	push_int 1
	get_local 0
	temp_arr_push

	push_int 1
	get_local 0
	temp_arr_push

	@fib_loop:

	push_int 1

	get_local 0
	temp_arr_len

	# Index of the last element stored in local 1
	sub

	# This is the last element
	get_local 1
	get_local 0
	# Store the last element in local 2
	index

	push_int 1
	get_local 1
	# Index of the second last element stored in local 2
	sub

	get_local 0
	# Store the second last element in local 3
	index

	add
	get_local 0
	temp_arr_push

	# Drop local 1, which was the length of the array, which we no longer need
	drop

	push_int 10

	get_local 0
	temp_arr_len

	# Jump if the array is larger than 10.
	lte
	jt @fib_loop
	`

	test(t, src, "[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]")
}

func TestFunction(t *testing.T) {
	src := `
	push_int 44
	push_function @subtract_two
	call
	halt

	@subtract_two:
		shift 1
		push_int 2
		get_local 0
		sub
		ret
	`

	test(t, src, "42")
}

func TestSimpleEnv(t *testing.T) {
	src := `
    push_int 404
    push_int 1
    push_int 405

    push_function @test
    # Add the local 1 to the environment.
    add_to_env 1
    call
    halt

    @test:
        push_int 2
        get_env 0
        add
        ret
    `

	test(t, src, "3")
}

func TestEscapedEnv(t *testing.T) {
	/*
	   fn create() {
	       var x = 0
	       return fn () {
	           x = x + 1
	           return x
	       }
	   }

	   var f = create()
	   var res = [f(), f(), f()]
	*/

	src := `    
    push_function @create
    call

    push_array

    get_local 0
    call
    get_local 1
    temp_arr_push

    get_local 0
    call
    get_local 1
    temp_arr_push
    
    get_local 0
    call
    get_local 1
    temp_arr_push
    halt

    @create:
        push_int 0
        push_int 404
        push_int 405
        push_function @create:anon_0
        add_to_env 0
        ret
    @create:anon_0:
        push_int 1
        get_env 0
        add
        set_env 0
        get_env 0
        ret
    `

	test(t, src, "[1, 2, 3]")
}

func TestMember(t *testing.T) {
	src := `
	push_array

	push_int 1
	get_local 0
	temp_arr_push

	push_int 2
	get_local 0
	temp_arr_push

	push_int 3
	get_local 0
	temp_arr_push

	get_member "length"
	call
	`

	test(t, src, "3")
}

func test(t *testing.T, src string, expected string) {
	bc := compile(t, src)
	vm := vm.New(&bc)
	err := vm.Run()
	require.NoError(t, err)

	res, err := vm.GetResult()
	require.NoError(t, err)

	require.Equal(t, expected, res)
}

func compile(t *testing.T, src string) code.Code {
	comp := text.NewCompiler(strings.NewReader(src))
	bc, err := comp.Compile()
	require.NoErrorf(t, err, "compilation from text format failed: %s", err)

	return bc
}